Background This study compared the clinical outcomes of transcatheter (TAVR) and surgical (SAVR) aortic valve replacements, focusing on postoperative valvular performance assessed by echocardiography. Method and Results A total of 425 patients who underwent TAVR (230 patients) or SAVR (195 patients) were included. Postoperative effective orifice area index (EOAI) was higher in the TAVR group (1.27 ± 0.35 cm2/m2) than in the SAVR group (1.06 ± 0.27 cm2/m2, p < 0.001), and patient–prosthesis mismatch (PPM) was more frequent in the SAVR group (22.6%) than in the TAVR group (8.7%, p < 0.001). Mild or greater paravalvular leakage (PVL) was more frequent in the TAVR group (21.3%) than in the SAVR group (0%, p < 0.001). Moreover, there was no difference in freedom from all-cause death, stroke, or rehospitalization between the groups. Patients with moderate or greater PPM (EOAI < 0.85 cm2/m2) had lower freedom from composite events than those without this PPM criterion (p = 0.008). Patients with mild or greater PVL also had lower freedom from composite events than those without this PVL criterion (p = 0.017). Conclusions Postoperative valvular performance of TAVR was superior to that of SAVR in terms of EOAI. This merit was counterbalanced by the significantly lower rates of PVL in patients who underwent SAVR. The overall clinical outcomes were similar between the study groups.